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A grease duct is a duct that vents grease-laden flammable vapors from commercial cooking equipment such as stoves, deep fryers, and woks to the outside of a building or mobile food preparation trailer. Grease ducts are part of the building's passive fire protection system. The cleaning schedule is typically dictated by fire code or related safety regulations.

Fire hazard

Vapors are created when grease is heated to and beyond its vaporization point. As the vapors cool, the grease condenses and settles on colder surfaces. Grease is a flammable hydrocarbon. A fire-resistance rating is required for the construction around the duct.

Design

In North America, grease ducts must be in compliance with NFPA 96 as well as the local building codes and fire codes.

A proprietary duct system that has its own inherent fire-resistance rating can be used, such as a metallic duct, either field fabricated or UL certified factory-built designs. Factory-built fire rated designs are tested to UL 1978 and UL 2221.

Maintenance and cleaning

Periodic cleaning is required. Compliance is proven through certificates issued by the cleaning and maintenance contractors. Purpose-designed fire suppression systems inside the hoods must also be routinely maintained.

Hazards associated with improperly maintained hoods include, but are not limited to, poor ventilation, excess heat and smoke, and the potential risk of fires.

See also

• Passive fire protection
• Duct (flow)
• Pressurisation ductwork
• Smoke exhaust ductwork
• Circuit integrity
• Kitchen exhaust cleaning
• Kitchen hood

References

1. "Hood Repair & Clean". Sunday, 2 May 2021
2. "Kitchen Exhaust Cleaning - Carolina Filters, Inc". www.carolinafilters.com. Archived from the original on 2017-07-21. Retrieved 2016-01-08.
3. "Duct Cleaning".

External links

• UL treatise on wrapping systems
• NFPA 96: Standard for Ventilation Control and Fire Protection of Commercial Cooking Operations Archived 2013-05-02 at the Wayback Machine
• ASTM E2336 Standard Test Methods for Fire Resistive Grease Duct Enclosure Systems
• ISO 6944-1:2008 Fire containment -- Elements of building construction -- Part 1: Ventilation ducts

v t e Fire protection
Fundamental concepts	Backdraft Boiling liquid expanding vapor explosion (BLEVE) Boilover Combustibility and flammability Conflagration Dangerous goods (HAZMAT) Deflagration Detonation Dust explosion Enthalpy of vaporization Explosive Fire class Fire control Fire loading Fire point Fire triangle Flammability diagram Flammability limit Flammable liquid Flashover Flash point Friction loss Gas leak Heat transfer Jet fire K-factor (fire protection) Pool fire Pyrolysis Spontaneous combustion Structure fire Thermal radiation Water pressure
Technology	Active fire protection Automatic fire suppression Condensed aerosol fire suppression Detonation flame arrester External water spray system Fire bucket Fire prevention Fire protection Fire retardant Fire-retardant fabric Fire retardant gel Fire-safe polymers Fire safety Fire sprinkler system Fire suppression system Firefighting foam Flame arrester Flame retardant Flashback arrestor Fusible link Gaseous fire suppression Hypoxic air technology for fire prevention Inerting system Intumescent Passive fire protection Personal protective equipment (PPE) Relief valve Spark arrestor Tank blanketing Vehicle fire suppression system
Building design	Annulus (firestop) Area of refuge Booster pump Compartmentation Crash bar Electromagnetic door holder Electromagnetic lock Emergency exit Emergency light Exit sign Fire curtain Fire cut Fire damper Fire door Fire escape Fire extinguisher Fire hose Fire hydrant Fire pump Fire sprinkler Firestop Firestop pillow Firewall (construction) Grease duct Heat and smoke vent Occupancy Packing (firestopping) Penetrant (mechanical, electrical, or structural) Penetration (firestop) Pressurisation ductwork Safety glass Smoke control Smoke damper Smoke exhaust ductwork Smokeproof enclosure Standpipe (firefighting)
Fire alarm systems	Aspirating smoke detector Carbon monoxide detector Circuit integrity Explosive gas leak detector Fire alarm call box Fire alarm control panel Fire alarm notification appliance Fire drill Flame detector Heat detector Manual fire alarm activation Smoke detector
Professions, trades, and services	Duct cleaning Fire insurance Fire protection engineering Fireproofing Fire-resistance rating Fire Safety Evaluation System (FSES) Fire test Kitchen exhaust cleaning Listing and approval use and compliance Sprinkler fitting
Industry organizations	Fire Equipment Manufacturers' Association (FEMA) Institution of Fire Engineers (IFE) National Council of Examiners for Engineering and Surveying (NCEES) National Fire Protection Association (NFPA) Society of Fire Protection Engineers (SFPE) Underwriters Laboratories (UL)
Standards	CE marking EN 3 EN 54 EN 16034 Flame spread GHS hazard statements GHS precautionary statements Life Safety Code (NFPA 101) List of R-phrases List of S-phrases Safety data sheet UL 94
Awards	Arthur B. Guise Medal Harry C. Bigglestone Award
See also	Template:Fire Template:Firefighting Template:HVAC
Category Commons

• Passive fire protection